07-09-2009
Help Understanding Output and question about /dev/
Hi,
I am having some problems understanding the info from the following output:
Disk /dev/sda: 17849 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/sda1 * 0+ 499 500- 4016218+ 83 Linux
/dev/sda2 500 999 500 4016250 82 Linux swap / Solaris
/dev/sda3 1000 17848 16849 135339592+ 83 Linux
/dev/sda4 0 - 0 0 0 Empty
I wan to know how large each partition is. I selected the size for /dev/sda2 in fdisk to be 1000M but if I am understanding the info correctly I only have 0.5megs for /dev/sda2. Can someone tell me how to effectively create partition sizes in fdisk? it seems when I try and specify the size using the actual size it does not work well.
One other question:
/dev/shm 517172 0 517172 0% /dev/shm
Is /dev/shm the swap partition /dev/sda2?
Thanks!
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LEARN ABOUT DEBIAN
prtvtoc
prtvtoc(1M) System Administration Commands prtvtoc(1M)
NAME
prtvtoc - report information about a disk geometry and partitioning
SYNOPSIS
prtvtoc [-fhs] [-t vfstab] [-m mnttab] device
DESCRIPTION
The prtvtoc command allows the contents of the label to be viewed. The command can be used only by the super-user.
The device name can be the file name of a raw device in the form of /dev/rdsk/c?t?d?s2 or can be the file name of a block device in the
form of /dev/dsk/c?t?d?s2.
OPTIONS
The following options are supported:
-f Report on the disk free space, including the starting block address of the free space, number of blocks, and unused parti-
tions.
-h Omit the headers from the normal output.
-m mnttab Use mnttab as the list of mounted filesystems, in place of /etc/mnttab.
-s Omit all headers but the column header from the normal output.
-t vfstab Use vfstab as the list of filesystem defaults, in place of /etc/vfstab.
EXAMPLES
Example 1: Using the prtvtoc Command
The following example uses the prtvtoc command on a 424-megabyte hard disk:
example# prtvtoc /dev/rdsk/c0t3d0s2
* /dev/rdsk/c0t3d0s2 partition map
*
* Dimension:
* 512 bytes/sector
* 80 sectors/track
* 9 tracks/cylinder
* 720 sectors/cylinder
* 2500 cylinders
* 1151 accessible cylinders
*
* Flags:
* 1: unmountable
* 10: read-only
* * First Sector Last
* Partition Tag Flags Sector Count Sector Mount Directory
0 2 00 0 76320 76319 /
1 3 01 76320 132480 208799
2 5 00 0 828720 828719
5 6 00 208800 131760 340559 /opt
6 4 00 340560 447120 787679 /usr
7 8 00 787680 41040 828719 /export/home
example#
The data in the Tag column above indicates the type of partition, as follows:
Name Number
UNASSIGNED 0x00
BOOT 0x01
ROOT 0x02
SWAP 0x03
USR 0x04
BACKUP 0x05
STAND 0x06
VAR 0x07
HOME 0x08
ALTSCTR 0x09
CACHE 0x0a
RESERVED 0x0b
The data in the Flags column above indicates how the partition is to be mounted, as follows:
Name Number
MOUNTABLE, READ AND WRITE 0x00
NOT MOUNTABLE 0x01
MOUNTABLE, READ ONLY 0x10
Example 2: Using the prtvtoc Command with the -f Option
The following example uses the prtvtoc command with the -f option on a 424-megabyte hard disk:
example# prtvtoc -f /dev/rdsk/c0t3d0s2
FREE_START=0 FREE_SIZE=0 FREE_COUNT=0 FREE_PART=34
Example 3: Using the prtvtoc Command on a Disk Over One Terabyte
The following example uses uses the prtvtoc command on a disk over one terabyte:.
example# prtvtoc /dev/rdsk/c1t1d0s2
* /dev/rdsk/c1t1d0s2 partition map
*
* Dimensions:
* 512 bytes/sector
* 3187630080 sectors
* 3187630013 accessible sectors
*
* Flags:
* 1: unmountable
* 10: read-only
*
* First Sector Last
* Partition Tag Flags Sector Count Sector Mount Directory
0 2 00 34 262144 262177
1 3 01 262178 262144 524321
6 4 00 524322 3187089340 3187613661
8 11 00 3187613662 16384 318763004
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO
devinfo(1M), fmthard(1M), format(1M), mount(1M), attributes(5)
WARNINGS
The mount command does not check the "not mountable" bit.
SunOS 5.10 25 Jul 2002 prtvtoc(1M)